A variety of hand tools have been developed including hand tools having folding implements. For example, hand held knives include knives having folding blade designs. By including folding implements, such as a folding pocket knife, a hand tool can include one or more implements in a relatively compact package. Moreover, the capability of folding an implement at least partially into the handle may increase the safety of these hand tools since the implements need not extend from the handle in instances in which the hand tool is not in use. For example, a knife having a folding blade design can be disposed in a folded configuration when not in use such that the cutting edge of the knife blade is safely disposed within the handle and will not be a safety hazard.
Although folding tools provide a relatively compact and safe form for the hand tool when not in use, folding hand tools generally require a locking mechanism to ensure that the implement that has been deployed is locked into position and will not fold up during use. Various locking mechanisms have been developed including, for example, liner locks and lockbacks. For example, a liner lock generally includes a liner plate disposed within the handle of the hand tool. The liner plate includes an elongate finger-like portion that is bent to extend at a slight angle toward the blade. As such, the distal end of the finger-like portion bears against a locking face of the blade when the blade is in an open position as a result of the elastic force provided by the finger-like portion. The liner lock therefore prevents the blade from being moved from the open position to a closed position without manually disengaging the liner lock. By way of another example, a lockback includes a spring disposed within the handle that includes a lug for engaging a corresponding notch or recess defined by the blade in order to secure the knife blade in an open position. The lockback must also be manually disengaged to permit the blade to fold into the closed position.
While liner locks and lockbacks as well as other conventional locking mechanisms are useful to secure a folding implement in an open position, it would be desirable to further improve the locking mechanisms employed by hand tools.